Fix traced StyleResolverStats

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 1846 matching lines @@
 
     // Pseudo element removal and similar may only work with these flags still set. Reset them after the style recalc.
     styleEngine().resetCSSFeatureFlags(resolver.ensureUpdatedRuleFeatureSet());
     resolver.clearStyleSharingList();
 
     ASSERT(!needsStyleRecalc());
     ASSERT(!childNeedsStyleRecalc());
     ASSERT(inStyleRecalc());
     ASSERT(styleResolver() == &resolver);
     m_lifecycle.advanceTo(DocumentLifecycle::StyleClean);
-    RefPtr<TracedValue> counters = shouldRecordStats ? resolver.stats()->toTracedValue() : nullptr;
-    TRACE_EVENT_END2("blink,blink_style", "Document::updateStyle",
-        "resolverAccessCount", styleEngine().resolverAccessCount() - initialResolverAccessCount,
-        "counters", counters);
+    if (shouldRecordStats) {
+        TRACE_EVENT_END2("blink,blink_style", "Document::updateStyle",
+            "resolverAccessCount", styleEngine().resolverAccessCount() - initialResolverAccessCount,
+            "counters", resolver.stats()->toTracedValue());
+    } else {
+        TRACE_EVENT_END1("blink,blink_style", "Document::updateStyle",
+            "resolverAccessCount", styleEngine().resolverAccessCount() - initialResolverAccessCount);
+    }
 }
 
 void Document::notifyLayoutTreeOfSubtreeChanges()
 {
     if (!layoutView()->wasNotifiedOfSubtreeChange())
         return;
 
     m_lifecycle.advanceTo(DocumentLifecycle::InLayoutSubtreeChange);
 
     layoutView()->handleSubtreeModifications();
@@ skipping 3885 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     WeakDocumentSet& set = liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().string().utf8().data());
 }
 #endif